Cable duplex system.



I. KITSEE.

CABLE DUPLEX SYSTEM. APPLICATION r1112 DBO. 22, 190p. RENEWED mu. 1,1911.

H m. Z mvnmm 01.2.. BY

AITDBIIEY- Patented Oct. 10, 1911.

or sr ISIDOR KITSEE, OF PHILADELPHIA, PENNSYLVANIA.

CABLE DUPLEX SYSTEM.

To all whom it may concern:

Be it known that I, Ismon Krrsnn, a citizen of the United States,residing in the city of Philadelphia, county of Philadelphia, and Stateof Pennsylvania, have invented a new and useful Cable Duplex Sys tem, ofwhich the following is a specificat1on.

My invention relates to telegraphy, and more particularly to telegraphyover lines or circuits in which there is great capacity causing wellknown disturbing effects.

More particularly my invention relates to duplex telegraphy wherein twomessages may be simultaneously transmitted over a line or cable inopposite directions without interference. To this end, I provide theapparatus, arrangement and system hereinafter described.

For an illustration of one of the forms my invention may take, referenceis to be had to the accompanying drawing, which is a diagrammatic Viewof the receiving and transmitting apparatus at two electricallyconnected but widely separated stations.

C is the line or cable which extends between the two stations, andassociated with the same are the two primary windings P and P of the twotransformers or convert ers T and T respectively, the primaries P and Pbeing connected between the cable or line C and the earth E. Thetransformer T is preferably of closed magnetic circuit type as shown,while the transformer T is preferably such as will permit an adjustmentor change or variation in the mutual induction between the primary andsecondary, so as to adjust, change or vary the inductive effect of theprimary P upon its secondary S To this end, the primary P and the core0, or either of them, may ad justably slide into and out of thesecondary S to vary the effect of the primary P upon the secondary S Thesecondary S of transformer T is serially connected with the secondary Sof the transformer T, the second ary being in a circuit including theinstrument R which may be a siphon recorder, relay, or any othertranslating or receiving device. The primary and secondary windings areso connected that, under the influence of current of a given directionin the primaries, the secondaries S and S deliver Specification ofLetters Patent.

Application filed. December 22, 1908, Serial No. 468,703.

Patented Oct. 10, 1911.

Renewed March 1, 1911. Serial No. 611,557.

currents in opposition to each other which, therefore, neutralize eachother and have no effect upon the instrument B. This neutralizing efiectis secured by the adjustment in transformer T previously mentioned,whereby the effect of the secondary S may be made exactly equal andopposite to the effect of secondary S. The primary P has preferably moreconvolutions and resistance than its secondary S, and the primary Ppreferably has more convolutions and resistance than its secondary S Ina circuit in shunt to the winding P are connected the opposed sources ofenergy 6 and b and an adjustable resistance r is provided. The sourcesI) and b are of clifferent powers, 5 being here shown, by way ofexample, and preferably, as of twice the power of b. The operators key70 controls a circuit in shunt to the source 5 By way of example merely,and Without limiting my invention to the proportions and values given,it may be stated that in connection with an Atlantic cable, I have usedapparatus as shown, the primary P having a resistance of about 1,000ohms, the secondary S a resistance of about 1,000 ohms, the primary P aresistance of about 158 ohms, and the secondary S a resistance of aboutsix tenths of an ohm; the source 5 consisting of 10 cells and the sourceb of 20 cells. I

In general, the operation is as follows: To transmit messages over theline or cable, the operator at each station manipulates his key 7c. Withthe keys open at both stations, there is no current in the line, thesources at one station being opposed to the sources at the other, but ateach station a current is flowing through each primary P. So it is thatif at both stations the operators open their keys at the same moments nocurrent is transmitted to line but the local current through the primaryP at each station affects the home receiver R to produce a signal as ifcoming from the distant station. With the key open at one station, theclosure of the key at the other station opposes the source b at onestation to the opposed sources 5 and b at the other station with aresultant current in the line equivalent to the power of the source Z)and in a given direction. This current traversing the line or cablepasses through the primary P at the distant station and induces acurrent in the secondary circuit to affect the receiver R, the

effect of the received impulse in the transformer T being insignificant.If the keys are closed at both stat-ions, there is no current on theline since the source b at one station will oppose and balance thesource b at the other station, but the local current in the primary Pwill induce a substantial impulse in the secondary circuit to affect thereceiver R, as if an impulse came from the distant station. The impulsesor currents flowing to line produce equal and opposite impulses in thesecondary circuit at the home station, so that the receiver is notaffected by impulses or currents transmitted from the same station.

From the foregoing description, it is apparent, therefore, without anartificial line or cable, I have provided a duplex system of cabletelegraphy in which the home instrument is not afi'ected by impulsestransmitted to line or cable from the same station, and wherein undercertain circumstances no current flows over the line or cable, but thereceiving instrument is aifected just as if a current were transmittedfrom the distant station.

What I claim is:

1. In telegraphy, the combination with a line or cable, of means fortransmitting and receiving current impulses, said means comprising twotransformers, a source of current and a receiving device, one winding ofeach transformer connected in the line or cable, the second winding ofeach transformer connected to the receiving device,

said source of current connected in shunt to one of said transformerwindings, said source being provided with means for transmitting oversaid line or cable impulses alternating in polarity.

2. In telegraphy, the combination with a line or cable, of means forsimultaneously transmitting and receiving messages between two stations,said means comprising for each station two transformers, a source ofcurrent and a receiving device, and means associated with onetransformer for neutralizing the home impulses on the home receiver,said source of current connected in shunt to one winding of atransformer and provided with means for transmitting impulses over saidline or cable.

3. The combination with a line, of two transformers, the primary of onetransformer being shunted by a circuit including opposed sources ofenergy, a key in a circuit in shunt to one of said sources, and a signaltranslating instrument.

. 4. The combination with a line, of two transformers, the primary ofone transformer being shunted by a circuit including opposed sources ofenergy of different powers, a key connected in a circuit in shunt to thesource of greater power, and a signal translating instrument.

5. The combination with a line, of two transformers, the primary of onetransformer being shunted by a circuit including opposed sources ofenergy, and a key in a circuit in shunt to one of said sources, a receiving instrument, the transformer secondaries included in circuitwit-l1 said receiving instrument, said secondaries producing equal andopposite effects under the influence of transmitted current.

6. The combination with a line, of two transformers, the primary of onetransformer being shunted by a circuit including opposed sources ofenergy of different powers, and a key connected in a circuit in shunt tothe source of greater power, a receiving instrument, the transformersecondaries included in circuit with said receiving instrument, saidsecondaries producing equal and opposite effects under the influence oftransmitted current.

7. The combination with a line, of two transformers of different ratiosof transformation, a signal translating instrument, a local circuitincluding the primary of the transformer of greater ratio oftransformation, opposed sources of energy in said local circuit, and akey controlling said sources.

8. The combination with a line, of two transformers of different ratiosof transformation, a local circuit including the primary of thetransformer of greater ratio of trans formation, opposed sources ofenergy in said local circuit, and a key controlling said sources, areceiving instrument, the transformer secondaries included in circuitwith said receiving instrument, said secondaries producing equal andopposite effects under the influence of transmitted current.

9. The combination with a line, of two transformers, a receivinginstrument, the transformer secondaries included in circuit with saidreceiving instrument, opposed sources of energy of different powers, theprimary of one transformer included in a local circuit with said opposedsources of energy of different powers, a key controlling said sources,and means for varying the mutual induction between said primary windingand its associated secondary.

10. The combination with a line, of two transformers, a receivinginstrument, the transformer secondaries being included in circuit withsaid receiving instrument, opposed sources of energy of differentpowers, the primary of one transformer included in a local circuit withsaid opposed sources of energy of different powers, and a key forcontrolling said sources, the secondary associated with said primarywinding having relatively low resistance.

11. The combination with a line or cable,

of a Windin associated therewith, a local In testimony whereof I havehereunto circuit inclu ing said Winding and opposed afiixeol mysignature in the presence of the sources of energy, and a key connectedin a tWo subscribing Witnesses.

circuit in shunt to one of said sources, and ISIDOR KITSEE. similarapparatus at a distant station, the sources at the tWo stations opposingand balancing each other.

Witnesses:

DANIEL WEBSTER, J r., A. E. STEINBooK.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. G.

